[EC] Use s2n-bignum point doubling for P-384 and P-521

[dkostic]

Issues:

N/A

Description of changes:

Use s2n-bignum point doubling for P-384 and P-521.
This brings the following performance improvements:

----|---- P-384 ---| before | after | speedup |
    | ECDH         |  4710  |  5256 |  1.11x  |
 M1 | ECDSA sign   | 12925  | 13322 |  1.03x  |
    | ECDSA verify |  5358  |  5884 |  1.10x  |
----|--------------|--------|-------|---------|
    | ECDH         |  3569  |  3822 |  1.07x  |
GV3 | ECDSA sign   |  9938  |  9915 |  1.00x  |
    | ECDSA verify |  4156  |  4466 |  1.07x  |
----|--------------|--------|-------|---------|
    | ECDH         |  4374  |  4777 |  1.09x  |
x86 | ECDSA sign   | 11982  | 12110 |  1.01x  |
    | ECDSA verify |  5102  |  5693 |  1.11x  |
----|--------------|--------|-------|---------|


----|---- P-521 ---| before | after | speedup |
    | ECDH         |  3406  |  3623 |  1.06x  |
 M1 | ECDSA sign   |  7060  |  7097 |  1.00x  |
    | ECDSA verify |  3199  |  3269 |  1.02x  |
----|--------------|--------|-------|---------|
    | ECDH         |  2297  |  2457 |  1.07x  |
GV3 | ECDSA sign   |  5163  |  5188 |  1.00x  |
    | ECDSA verify |  2346  |  2512 |  1.07x  |
----|--------------|--------|-------|---------|
    | ECDH         |  2981  |  3272 |  1.10x  |
x86 | ECDSA sign   |  6550  |  6575 |  1.00x  |
    | ECDSA verify |  3121  |  3352 |  1.07x  |
----|--------------|--------|-------|---------|

The x86 processor is Intel(R) Xeon(R) Platinum 8488C.

Call-outs:

Point out areas that need special attention or support during the review process. Discuss architecture or design changes.

Testing:

How is this change tested (unit tests, fuzz tests, etc.)? Are there any testing steps to be verified by the reviewer?

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license and the ISC license.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 78.69%. Comparing base (7c04616) to head (66b4a3d).
Report is 8 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2011      +/-   ##
==========================================
+ Coverage   78.62%   78.69%   +0.07%     
==========================================
  Files         596      598       +2     
  Lines      102745   103326     +581     
  Branches    14599    14687      +88     
==========================================
+ Hits        80780    81311     +531     
- Misses      21314    21363      +49     
- Partials      651      652       +1     

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